tonight on "nightline." food fix? could overeating really be an addiction? the story of one woman who went on a simple program to break the vicious cycle of gaining and losing and gaining again. and the jfk tapes. the secret oval office recordings from private worry over civil rights, to tender moments between a president and his children. tonight car line kennedy tells diane sawyer what she learned from her father, an abc news exclusive. and fresh off the big emmy win. tom bergeron is telling us all about the all-star season of the show that launched an american

ballroom dancing obsession. good evening. i'm cynthia mcfadden. tonight, sweet, salty and addictive. it's a controversial theory but some doctors claim you can actually get hooked on food and that sugary processed foods can work on your brain like a drug. others say addiction doesn't apply when it comes to food something you need to survive. abc's juju chang met won woman who try aid three-step program to lose the pounds for good and gain control of her life. >> reporter: tara calls herself a recovering addict, the substance she abused, food. the former plus-sized model

wasn't overeating, she was out of control. >> give me the experience. >> i would get wing, ben and jerry's and that meal alone was probably around 6,000 calories if not more. >> reporter: by the age of 22 she tipped the scales at 316 pounds and then decided to shed the weight in the most public way possible on the tv show "the biggest loser" she lost an astonishing 155 founds. landed on the cover of magazines like ok! and woman's world. when she started to creep back, she realized it was not about her body but mind. doctor says tara is not alone. >> organic changes that happen in the reward system are identical to whether it's drug,

alcohol or food. >> if might be flying american's obesity epidemic. four americans die of obesity related diseases than cancers combined. food can be as addictive as cocaine. >> you're secreting lots of pleasure reward brain chemical called dope mean. it's coming out and giving you that fantastic feeling of, wow, this is wonderful. >> reporter: for compulsive eaters like tara, recognizing she had an addiction was like a thunder clap to her brain. >> that makes me feel good. >> reporter: in her new book, the doctor offers a prescription to get on the way to recovery. three ms. mind, memory and mouth. we reveal the snacks we crave

most. for me it's cheese. >> you're a fatty girl that also likes salt. >> what did you call me. >> what did you call me? >> you like fatty w salt. >> reporter: for now, we head to send tlal park. it's time to medicate. >> i'm in control. i'm powering up my brain. >> this is not a new age moment. this is hard core neuroscience. you're powering up the brain to stay vigilant, say no and rein in impulses. >> reporter: step two. instead of ice cream we try a chocolate protein smoothie. >> there's not sugar in it. >> peanut butter. one of my favorite things. step three, move your muscles. >> she rewards her brain with

endorphins. >> now if i have too much sugar i get violently sick. >> new science shows you increase the size of the brain because you stimulate brain growth. when you do things like physical activity. you induce changes in your genes. >> reporter: these scans show the reward senters reacting to a chocolate milkshake. for some people the pleasure receptors turn off. for others it keeps reacting, wanting more. by focusing on the three ms. mind, mouth and muscle. the doctor thinks you can restrain the brain. tara is in what dr. peak calls master recovery. she did something beyond her wild dreams. finished an iron man triathlon. >> no dream is improblem. >> reporter: tara said she'll be

a recovering food addict but knowing that is a victory. >> i wish i could be normal with it. but it will be okay. >> "the hunger fix " is in stors now. up next the president's candid moments. secret recordings of john f. kennedy. plus "dancing's" biggest stars back. we talked with tom bergeron about dancing with the all stars. and retire with more? then don't get nickle and dimed by high cost investments and annoying account fees. at e-trade, our free easy-to-use online tools and experienced retirement specialists can help you a personalized plan. and with our no annual fee iras and a wide range of low cost investments, you can execute the plan you want at a low cost. so meet with us, or go to etrade.com for a great retirement plan with low cost investments.

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fifteen minutes could save you fifteen percent or more. news now from the time capsule. we step back to 1960s. john f. kennedy is president and tonight, we learn that he had

secretly installed microphones in the oval office controlled only by him recording over 200 hours behind closed doors. from national crises to tender family moments including ones with his daughter caroline who talked with abc's diane sawyer about the father she holds dear. >> reporter: you were there inside a presidential life. 265 hours of secret audiotapes. and listening to them all these years later a little girl all grown up who remembers the serious voices around her as she made paper clip necklaces in her favorite play house. >> i remember clearly being under the desk and trying to get candy from the grown ups around. obviously our dream was to be allowed into the office to see him. i used to go before school or walk over before school. >> reporter: caroline kennedy

said it's wonderful to hear him laughing when she walks in demanding attention. >> i'll see you later. >> i won't let you do much. >> that sound is little john, pounding under the desk no idea he's hitting a microphone. his father, relaxed. >> seeing him at work and seeing him in the present, in a way was like being in his company while you're listening. i think that was really wonderful feeling for "m." >> what you hear on the tape is a man impoply calm in crisis. he discovered the soviets placed nuclear missiles inside cuba aimed at the u.s. >> in other words you're in a pretty bad fix. >> you're in there with me. >> reporter: however calm and

steady in the cuban missile crisis he could unleash irritation on small things. here the defense department official spent a lot of money on furniture for a president mrs. kennedy if she went into labor and he's fur use. >> i want to find out who paid for it and i want that fellow competent. i won't have him running a cathouse. >> reporter: in another point he noticeds u.s. hockey team got shellacked by the sweeds? >> who are we sending over there, girls? >> nowhere are the tapes more revealing than the secret witness to the struggle for civil rights. the great moral issue tearing the country apart. >> the worst city in the south have done nothing for the negroes. >> reporter: after a young man, named james meredith creates a crisis by enrolling in the all-white university of

mississippi. >> james meredith was inspired by my father's address. and ziepd r decided he wanted to enroll in mississippi. >> reporter: this was as the governor of mississippi wanted to eject meredith into an angry mop? >> why don't you remove him? >> how can i remove him if there's a riot in the street. >> barnett is pushing for him to cave. >> it's really an incredibly tense standoff between the two of them. >> kennedy spent the national guard and james meredith became the first black graduate of ole miss. outside the riots, flames, and darkness settling in. it is his last november, the president sounds exhausted.

>> politically the noise sounds disturbing. >> a little boy climbs into his lap. >> why do the leaves fall? where do we go to the cape? to hyannis port? >> because it's summer. >> reporter: days before he's assassinated -- >> tuesday, november 12th. >> reporter: the last words on the last tape are about the hard battle ahead. >> our lot becomes more difficult. >> our lot becomes more difficult. and that's it. >> i love that. i think that's really -- i thought it was really moving and obviously knowing what happened, he understood how difficult all of this really was. >> john kennedy once told his friends life is a struggle.

and to be struggle is to struggle in a tremendous sort of arena. >> that's what the presidency is. >> that's great. you're hopefully making things better. i think that's the most rewarding life you could have. i think he did that. >> listening in the secret white house recordings of john f. kennedy is in book stores tomorrow. caroline kennedy will talk to them in the morning. our thanks to diane. up ahead. from emmitt smith to shawn johnson. the "dancing with the stars" all-stars returns to the stage and tom bergeron gives you the inside scoop. hey america, even though

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well, pull out those dancing shoes. the hit phenomenon is back. this time "dancing with the stars" fan favorites are returning to the stage for another chance of victory fresh on the heels of a big emmy win. tom bergeron talks to abc's david wright about the

star-studded lineup. welcome to "dancing with the stars" the all-stars -- >> tonight the host of america's favorite ballroom show has a new dance partner himself. the winged woman on that emmy statuette tom bergeron took home last night an award p bergeron won for making "dancing with the stars" smooth as all of those dance moves. >> a celebrity ballroom competition, really. when i was first pitched the show i thought this can't work. this is a porch of people coming out of their comfort zone as a lark. >> reporter: on live tv the unexpect unexpected does happen. planting a big wet kiss right on the lips. bergeron handled it with star. a few weeks back marie osmond hit the stage with her samba -- right after the samba -- >> that was the most dramatic

thing. usually it's somebody popping out of a dress i'm always happy to help them back in. respect rth tonight on the season opener, deja vu. joey fatone, bristol pay len and pamela anderson who vowed to stay se stay celebat. over her shoulder with her back to me she said i'm already off the wagon. >> reporter: some of the toughest competitors. >> we've got the first four champions. kellie monaco. emmett smith, hello. shawn johnson. >> shawn johnson is the gold medalist who try atriumph ped.

>> we have one, two three of my season. that's infilm datimidateintimid. they're out to get me. >> gilles marini came in second. six of them won. why are you calling me the front-runner. i'm clearly not. >> the third place finisher, former dallas cowgirl melissa rycroft. >> last time around is a particularly tough time in your life. . not a highlight. >> last time she appeared on "dancing with the stars" after she had been proposed to on "the bachelor." only to be famously dumped by her new fiance on "after the final rose." >> to me getting engaged and finding that person was a once in a lifetime thing and you took that from me. >> season 8 i came off a

humiliating time of my life. >> this time around all of the stars faced new challenges. they faced ups and downs. >> some have not been dancing in quite a while. >> each of them know this particular mirror ball trophy know there's a status for fans of the show coming into a season of all-stars and walking away with that one. >> for all of these stars the pressure is on and having done it before they know what they're in for. >> my daughter is asking me every day when i'm coming back with the trophy. >> she may get her wish or not. after tonight he's running a very close second place. >> thank you "nightline." this is awesome. >> i'm david wright for "nightline" from hollywood. >> thank you for watching abc news. jimmy kimmel is next. we'll see you right back here tomorrow. good